There must be lots of tutorials around about making movies with games and which would be a great help to those just starting out on their Machinima adventure. I was able to find these two interesting articles,
Firstly a great 101 for those wishing to start with the Sims4,
And an interview with an experienced film-maker who is using Grand Theft Auto V, Red Dead Redemption2 and other games.
If you know of others that would be useful please post them in the Forum.